They pointed out that, at the levels consumed in the West, sugar alters metabolism, raises blood pressure, disrupts hormone signalling, and causes significant damage to the liver that is still not fully understood.

Professors Robert Lustig, Laura Schmidt and Claire Brindis argue that sweetened food is indirectly responsible for 35 million annual deaths worldwide as a result of conditions such as heart disease, diabetes and cancer.

Setting out their views in the science journal Nature, they called for a number of urgent measures to be taken to address the issue.

One strategy was to add taxes to processed foods that contain any form of added sugar, including carbonated drinks, juice, chocolate milk and sugared cereals.

They also called for tighter controls over access to sugar including strict measures such as age limits on the purchase of sugary drinks as well as tighter controls on vending machines and snack bars in schools and workplaces.

“We're talking about gentle ways to make sugar consumption slightly less convenient, thereby moving people away from the concentrated dose.

"What we want is to actually increase people's choices by making foods that aren't loaded with sugar comparatively easier and cheaper to get."

However, she also stressed that the first step towards a shift in attitudes would be to educate the public about the science of sugar.

"There is an enormous gap between what we know from science and what we practice in reality.

"In order to move the health needle, this issue needs to be recognised as a fundamental concern at the global level."

Ursula Arens, spokesperson for the British Dietetic Association, warns of the implications of introducing an age limit for the purchase of sugary drinks.

“This would not only be unrealistic and incredibly burdensome for retailers, it would also imply there is a similar risk for a child having a can of Coke as having a beer,” she told The Huffington Post.

Arens suggests that the introduction of new laws is not the most effective way to tackle the issue of sugar consumption. Rather she recommends ongoing communication with both food companies and retailers.

“Measures are already being taken by food companies, retailers and restaurant chains to help educate the public on the health risks of sugar.

"An increasing number of fast food chains such as Pret and McDonald’s now display nutritional information for their customers while many food products have front-of-pack labels that display the % of the recommended daily intake of sugar so consumers can make informed choices.

"Before we introduce new and complex laws, let's monitor the effects of this availability of information."

However, Arens does agree that further government action could be taken.

"Further public funding would help to educate both teachers and parents to instill the message that sweets should be seen as treats."

Speaking about the comment article, Prof Lustig, from the UCSF Benioff Children's Hospital, said, as reported by the Press Association: "As long as the public thinks that sugar is just 'empty calories', we have no chance in solving this.

"There are good calories and bad calories, just as there are good fats and bad fats, good amino acids and bad amino acids, good carbohydrates and bad carbohydrates. But sugar is toxic beyond its calories."

Worldwide consumption of sugar has tripled in the last 50 years, fuelling a global obesity epidemic.

The main culprit is said to be fructose, a sugar molecule that is commonly added to processed food in sweetening agents such as high-fructose corn syrup (HFCS). There is increasing evidence that excess fructose has harmful effects on the body.

The experts concluded in their article: "Regulating sugar will not be easy - particularly in the 'emerging markets' of developing countries where soft drinks are often cheaper than potable (drinking) water or milk.

"We recognise that societal intervention to reduce the supply and demand for sugar faces an uphill political battle against a powerful sugar lobby, and will require active engagement from all stakeholders."